507. Carex enervis C. A. Meyer in Ledebour, Fl. Altaic. 4: 209. 1833.
无脉薹草 wu mai tai cao
Carex enervis subsp. chuanxibeiensis S. Yun Liang & Y. C. Tang; C. stenophylla Wahlenberg var. enervis (C. A. Meyer) Kükenthal.
Rhizome thick, long creeping. Culms 10-30 cm tall, trigonous, slightly curved, scabrous above, clothed with pale brown sheaths at base. Leaves shorter than culm, blades gray-green, linear, 2-3 mm wide, flat or plicate, margins scabrous, apex acuminate. Involucral bracts setaceous or glumelike. Spicate inflorescence ovate or oblong, 1-2 × 0.7-1.4 cm; spikes numerous, androgynous. Female glumes pale brown to ferruginous, oblong or broadly ovate, 3-3.5 × 1.8-2 mm, margins narrowly white hyaline, 1-veined costa forming a mucro, apex acute or acuminate. Utricles stramineous to ferruginous, ± equaling glume, oblong-ovate or elliptic, plano-convex, ca. 3 × 1.2 mm, papery, usually nerveless or several veined at base abaxially, nerveless adaxially, base subrounded or cuneate, margins thickened, apex gradually tapering into a scabrous-margined beak, orifice pale hyaline, 2-toothed. Nutlets pale gray, tightly enveloped, elliptic-obovate, 1.2-1.5 × ca. 1 mm, lustrous; stigmas 2. Fl. and fr. Jun-Aug.
Wet places, roadsides, meadows, swamps; 2500-4500 m. Gansu, Heilongjiang, Jilin, Nei Mongol, Qinghai, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan [Mongolia, Russia (Siberia)].